The court has the final say on issues such as abortion and gun control.

A final vote on whether Judge Kavanaugh will join the nine-member panel is scheduled for Saturday. If confirmed, the position is for life.

Hours before the undecided senators indicated their backing, the US Senate narrowly advanced President Donald Trump’s nominee to a final vote by voting to strictly limit debate on the issue.

The political fallout from the Kavanaugh vote

Friday’s “cloture” vote – 51-49 in favour – was a test of support for the embattled nominee who has faced sexual assault allegations from several women, including Prof Christine Blasey Ford.

What did the Senators say?

Senator Collins ended hopes she would side with her Democratic colleagues in the final vote, telling Senate colleagues she did not believe the “charges can fairly prevent Judge Kavanaugh from serving on the court”.

“The facts presented do not mean that Professor Ford was not sexually assaulted that night or at some other time but they do lead me to conclude that the allegations failed to meet the more likely than not standard,” she said.

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Media captionCollins: I vote to confirm Judge Kavanaugh

Senator Manchin, who is up for re-election in West Virginia, a traditionally Republican state that Mr Trump won by a landslide, told the Senate moments later he “found Judge Kavanaugh to be a qualified jurist who will follow the constitution and determine cases based on the legal findings before him”.

What has the reaction been?

The reaction has been swift, with former president George HW Bush and White House press secretary Sarah Sanders both tweeting their support for Ms Collins.

Mr Manchin, however, has found himself in the firing line.

A liberal group which raises money for Democratic candidates, Priorities USA, immediately said it would not be giving any funds to his re-election campaign.

Outside, protesters shouted “shame on you” as Mr Manchin spoke to reporters about his decision.

Meanwhile, a tweet asking someone to run for Ms Collins’ seat in Maine when it comes up for re-election in 2020 from former White House communication chief, Jen Psaki, had a swift response from former UN ambassador Susan Rice.

She later clarified she was “not making any announcements” but was ” deeply disappointed in Senator Collins’ vote for Kavanaugh”.

Alaska’s Lisa Murkowski – a Republican who voted against the nomination earlier on Friday – is yet to officially say which way she will vote on Saturday.

However, former vice-presidential candidate Sarah Palin tweeted she could “see 2022 from my house”, inferring she would fight for her seat should she not side with her Republican colleagues in the vote to confirm Judge Kavanaugh.

Analysis: Just the beginning

by Anthony Zurcher, BBC North America reporter

Brett Kavanaugh’s confirmation to the Supreme Court is all but certain. The Republican Party has the votes and the battle appears over. The political war, however, is just beginning.

Donald Trump’s court pick generated a controversy that captured the nation’s attention in a way that few political issues do. It generated daily headlines rivalled only by the US quadrennial presidential elections.

Now that the bombs have been thrown, it’s time to assess the fallout.

Read more from Anthony

What was the FBI inquiry about?

Judge Kavanaugh has faced sexual assault allegations from several women, most prominently from Prof Ford.

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Media captionChristine Blasey Ford said she was “100%” sure Brett Kavanaugh assaulted her

In public testimony last week Prof Ford said she had been assaulted by Judge Kavanaugh when they were both teenagers in 1982.

Judge Kavanaugh denied the claim – and allegations that he drank to the point of memory loss at the time – in a feisty confrontation with senators.

After the testimony, President Trump agreed to a new FBI inquiry.

Why sexual assault survivors forget details

Ford’s testimony through the eyes of a survivor

Federal agents are believed to have spoken to five witnesses regarding Prof Ford’s accusations and another four other witnesses involving a separate accusation by Deborah Ramirez, who said the nominee had exposed himself to her when they were both at Yale University. He denies Ms Ramirez’s allegations, too.

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Media captionFeinstein and McConnell have very different views on the FBI report

Mr Trump and his fellow Republicans said the new FBI report had cleared their nominee.

But Democratic senators said it had been incomplete.

The lawyers of both women have also complained that several witnesses they had offered to the FBI to corroborate their claims had not been contacted at all.